环己酮蒸馏塔真空度对理论塔板数的影响

Influence of vacuum on theoretical plate number in cyclohexanone column

在己内酰胺生产过程中 ,环己酮蒸馏塔的作用是利用环己酮与环己醇沸点差异 ,将二者分离。讨论了环己酮和环己醇汽 -液相平衡关系 ,绘制了常压及 10kPa时的温度与摩尔分率 (t-x - y)图及液 -汽相关系 (x - y)图。分析了系统压力对沸点差、相对挥发度、理论塔板数、操作回流比的影响。认为 :( 1)降低压力 ,提高真空度 ,可使二者沸点差拉大 ,相对挥发度随之提高 ,环己酮蒸馏塔的理论塔板数、回流比逐渐递减 ,但压力降低到一定程度时 ,变化缓慢 ,故应选择一最佳压力值 ;( 2 )压力由常压变化到 10kPa时 。

The cyclohexanone column was used to separate cyclohexanol and cyclohexanone by the difference of their boiling points in production of hexanolactam. The gasliquid phase equibrium of cyclohexanol and cyclohexanone was discussed by drawing temperaturemole percent relation picture, and liquidgas phase relation picture under normal pressure and 10kPa. The influence of system pressure on difference of boiling points,relative volatility, theoretical plate number, and reflux ratio was analysized.It was showed as follows.(1) If the pressure was dropped,i.e.the vacuum was increased, the relative volatility would increased too, while the theoretical plate number and reflux ratio would decreased gradually. But when the pressure was dropped to a certain degree, the change was so slow that an optimum pressure value should be selected.(2)With the pressure changed from normal atmosphere to 10kPa, the relational factor of Gilliland had few changes.